High-rise buildings are usually provided with numerous elevators, escalators and other corresponding transport facilities for carrying passengers between different floors. When passengers input elevator calls at floor landings, the elevator group control system allocates elevators (elevator cars) to the passengers on the basis of desired optimization criteria. In an ordinary elevator system, call input is effected using up/down buttons located in elevator lobbies, by means of which the passenger calls an elevator and at the same time indicates the intended traveling direction. Upon arrival of the elevator car at the call input floor, the passenger enters the car and indicates his/her destination floor by means of destination floor buttons provided in the elevator car. However, the above-described call input method is impractical and often inefficient, which is why call input in elevator systems is increasingly implemented using so-called destination call systems, in which each passenger indicates the intended destination floor already at the departure floor, e.g. in the entrance hall, before entering an elevator car. Destination calls are input via a specific destination call terminal using either buttons or an electrically readable identifier. In destination call systems, an allocation decision is generally made immediately upon registration of the call. In traditional elevator systems, in which a call is input using up/down buttons, the allocation decision can be delayed up to a moment when there still remains enough time for the allocated elevator to stop at the call input floor.
The calls input by passengers are thus generally registered in the group control system of the elevator bank, which allocates to the passenger an elevator that best meets the given optimization criteria. Based on the allocation result, the group control system sends the required commands to the elevator controller of the allocated elevator for picking up the passenger from the departure floor and transporting the passenger to the destination floor chosen by the passenger. If the passengers are using an elevator bank consisting of a large number of elevators, e.g. more than eight elevators, the allocation calculation will be a highly calculation-intensive optimization task. Therefore, in the case of prior-art elevator banks in which the allocation task is solved in the group control system of the elevator bank, an optimal allocation result can not necessarily be reached due to lack of time and/or the calculation takes an immoderately long time. There is thus a need for a solution in which the calculation load can be reduced by decentralizing the calculation of optimal elevator routes within the elevator system.